ASS1 and Miyoshi myopathy: Quantification by real time RT-qPCR analysis of ASS1 and ASL transcripts showed increased expression when MM cell lines were cultured in medium containing low arginine concentration (11 μM), as compared to cells cultured in standard arginine concentration (1140 μM) (Supplementary Figure 1), indicating that MM cells respond to arginine deprivation by increasing its biosynthesis.